Ministry of Education Key Laboratory for Analytical Science of Food Safety and Biology, Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350116, China.
Ministry of Education Key Laboratory for Analytical Science of Food Safety and Biology, Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350116, China.
Talanta. 2018 Feb 1;178:563-568. doi: 10.1016/j.talanta.2017.09.043. Epub 2017 Sep 19.
In most aptamer based stimulus response mesoporous silica nanoparticles (MSN) systems, the aptamer is modified on the MSN via electrostatic interaction, however leakage might exist after a certain time in the system and hence the stability is not good. In this study, the pores of MSN were capped by aptamer through click chemistry reaction for the first time and the system was then employed to develop a fluorescence biosensor. Specifically, the aptamer of the target (thrombin in this study) was hybridized with its complementary DNA (which was initially modified with alkyne at the terminal) to form a double strand DNA (dsDNA) firstly, and then this dsDNA was modified on N modified MSN via Cu(I) catalyzed alkyne-azide cycloaddition reaction. The guest molecules (fluorescein) were blocked in the pores of the MSN with high efficiency and nearly no leakage was detected. Upon the introduction of thrombin, thrombin specifically recognized its aptamer, so aptamer released from the MSN; and the single strand DNA(ssDNA) left could not cap the pores of the MSN efficiently and hence caused the releasing of fluorescein into the solution. The enhanced fluorescence intensity of the system has a good linear relationship with the thrombin concentration in the range of 50-1000ngmL with a detection limit of 28.46ngmL. The proposed biosensor has been successfully applied to detect thrombin in serum samples with high selectivity. The same strategy can be applied to develop biosensors for different targets by changing the adopted aptamer.
在大多数基于适体的刺激响应介孔硅纳米粒子（MSN）系统中，适体通过静电相互作用修饰在 MSN 上，然而在系统中经过一定时间后可能会存在泄漏，因此稳定性不好。在本研究中，首次通过点击化学反应将 MSN 的孔用适体封闭，然后将该系统用于开发荧光生物传感器。具体来说，首先将目标物（本研究中的凝血酶）的适体与与其互补的 DNA（其末端最初用炔烃修饰）杂交形成双链 DNA（dsDNA），然后通过 Cu(I)催化的炔烃-叠氮环加成反应将该 dsDNA 修饰在 N 修饰的 MSN 上。客体分子（荧光素）被高效地阻挡在 MSN 的孔中，几乎没有检测到泄漏。当引入凝血酶时，凝血酶特异性地识别其适体，因此适体从 MSN 中释放出来；而留下的单链 DNA（ssDNA）不能有效地封闭 MSN 的孔，从而导致荧光素释放到溶液中。该系统的增强荧光强度与 50-1000ngmL 范围内的凝血酶浓度呈良好的线性关系，检测限为 28.46ngmL。该生物传感器已成功应用于血清样品中凝血酶的高选择性检测。通过改变采用的适体，相同的策略可以应用于开发不同靶标的生物传感器。
